1. Field of the Invention
The present invention relates to a liquid crystal display apparatus serving both as a transmission type and a reflection type and a method of manufacturing the same.
2. Description of the Related Art
As a liquid crystal display apparatus serving both as a transmission type and a reflection type, an apparatus using translucent pixel electrodes and half-reflecting pixel electrodes is known. In such a liquid crystal display apparatus, in general, a liquid crystal is sealed between first and second substrates, a plurality of transparent pixel electrodes are arranged in a matrix form on an inner surface of the second substrate which is opposite to the display surface side of the two substrates, a half mirror is formed on the surface of each transparent pixel electrode, and a backlight is placed on the outer surface side of the second substrate.
When the above conventional liquid crystal display apparatus is to be used as a transmission type, the backlight is turned on. Light from the backlight is transmitted through the second substrate, transparent pixel electrodes, half mirrors, liquid crystal, and the first substrate on the display surface side, and emerges from the display surface side of the first substrate, thereby performing display operation.
When the above conventional liquid crystal display apparatus is to be used as a reflection type, the backlight is not turned on. In this case, external light incident from the display surface side of the first substrate is transmitted through the first substrate and liquid crystal and is reflected by the half mirrors. The reflected light is sequentially transmitted through the liquid crystal and first substrate and emerges from the display surface side of the first substrate, thereby performing a display operation.
For example, half mirrors in the above conventional liquid crystal display apparatus are formed as follows. A high-reflectance thin metal film made of aluminum or the like is formed by a sputtering method on an insulating film and a plurality of pixel electrodes formed on the insulating film. Fine holes are then formed in the thin metal film by a photolithographic method, and portions of the thin metal film which do not correspond to the pixel electrodes are removed. With this process, half mirrors formed from the thin metal film having fine holes are formed on the surfaces of the respective transparent pixel electrodes.
According to another method of forming half mirrors, a high-reflectance thin metal film having defective portions is formed by the sputtering method on an insulating film and a plurality of transparent pixel electrodes formed on the insulating film. Portions of the thin metal film which do not correspond to the pixel electrodes are then removed by the photolithographic method. With this process, half mirrors formed from the thin metal film having defective portions are formed on the surfaces of the respective transparent pixel electrodes.
According to the above conventional liquid crystal display apparatus, half mirrors are formed in the dedicated manufacturing steps, and hence the number of manufacturing steps is large, leading to an increase in cost.